1. What is 3-Phase Motor Power Calculation?

The 3-phase motor power calculation determines the real power consumed by an electric motor based on voltage, current, power factor, and efficiency. This is essential for sizing pumps, selecting proper wiring, and calculating energy consumption.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

Where:

• \( P \) — Power (kW)
• \( V \) — Line voltage (Volts)
• \( I \) — Line current (Amps)
• \( PF \) — Power factor (0-1)
• \( \eta \) — Motor efficiency (0-1)

Explanation: The √3 factor accounts for the phase difference in 3-phase systems. The formula calculates real power (kW) rather than apparent power (kVA).

3. Importance of Power Calculation

Details: Accurate power calculation helps in proper motor selection, energy efficiency assessment, electrical system design, and operational cost estimation.

4. Using the Calculator

Tips:

• Measure voltage between any two phases (line-to-line)
• Current should be measured on one phase
• Typical power factor for motors: 0.8-0.95
• Typical motor efficiency: 0.85-0.95

5. Frequently Asked Questions (FAQ)

Q1: Why divide by 1000 in the formula?
A: The division converts watts to kilowatts (kW) for more practical units.

Q2: What's the difference between real and apparent power?
A: Real power (kW) does actual work, while apparent power (kVA) includes reactive power. The ratio is the power factor.

Q3: How does voltage affect motor power?
A: Power is directly proportional to voltage. A 10% voltage drop results in about 10% power reduction.

Q4: What if I only have single-phase measurements?
A: For single-phase systems, use P = V × I × PF × η (without the √3 factor).

Q5: How accurate are typical motor efficiency values?
A: Actual efficiency depends on load. Motors are most efficient at 75-100% load. Nameplate values are for full load.